Recent developments in the field of newborn hearing screening and pediatric cochlear implantation have led to extraordinary benefits for many children with born with severe-profound sensori-neural hearing loss. Receiving a cochlear implant by 12-18 months of age coupled with early training in spoken language communication often leads to spoken language skills which are similar to that of typical, hearing children by kindergarten age. While some language deficits may still exist, these children are proficient enough in the language of the surrounding "hearing" community to be able to fully participate in mainstream educational, family and community experiences. The broad objective of this continuation project is to explore the new boundaries of cochlear implantation and to establish long-term outcomes of evolving surgical practices. In Aim 1, we will diagnose the specific spoken language deficits that remain after implantation between the ages of 1-3 years and to examine the role of even earlier cochlear implantation - below the age of 12 months -- in the amelioration of those deficits. In Aim 2, we will assess the role of the specific timing of implantation in infancy on the child's acquisition of a normal speech sound repertoire. While spoken language skills may be adequate, speech articulation may still have room for improvement. Finally, we will determine the long-term benefits of very early cochlear implantation on the speech perception, production, language and literacy skills of 10-year-old children who received a cochlear implant in infancy in Aim 3. Currently, we can measure significant differences in spoken language skills conferred to preschoolers who receive an implant closer to their first birthday than to their second birthday. These advantages are significant even when controlling for length of cochlear implant use. It is important to know whether these advantages remain evident during the elementary school years or whether those who receive the implant somewhat later are able to catch up. Across the U.S., there are children currently receiving implants between the ages of 6-12 months - below the current FDA guideline. It is crucial to gather outcome data to understand whether this evolving practice is warranted. We will test 25 children nationwide who have received an implant below 12 months of age. Detailed speech/language analyses will determine whether this practice produces measurable and meaningful benefits for children. For longterm outcomes, we will test 60 children (from our longitudinal sample) who will undergo a 2-day battery of tests to evaluate differences due to age at implantation and to establish their current level of skill in speech, language and cognitive functioning. The findings of this study will inform parents, surgeons, teachers, clinicians and policy-makers in their efforts to determine the protocol for early cochlear implantation with the highest likelihood of leading to optimal spoken language skills.